Using a high-throughput screening strategy, a series of 1-aryl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-4-ones was identified that inhibit the cyclin-dependent kinase (CDK) 4/cyclin D1 complex-mediated phosphorylation of a protein substrate with IC(50)s in the low micromolar range. On the basis of preliminary structure-activity relationships (SAR), a model was proposed in which these inhibitors occupy the ATP-binding site of the enzyme, forming critical hydrogen bonds to the same residue (Val96) to which the amino group in ATP is presumed to bind. X-ray diffraction studies on a later derivative bound to CDK2 support this binding mode. Iterative cycles of synthesis and screening lead to a novel series of potent, CDK2-selective 6-(arylmethyl)pyrazolopyrimidinones. Placement of a hydrogen-bond donor in the meta-position on the 6-arylmethyl group resulted in approximately 100-fold increases in CDK4 affinity, giving ligands that were equipotent inhibitors of CDK4 and CDK2. These compounds exhibit antiproliferative effects in the NCI HCT116 and other cell lines. The potency of these antiproliferative effects is enhanced in anilide derivatives and translates into tumor growth inhibition in a mouse xenograft model.

中文翻译：

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细胞周期蛋白依赖性激酶的1-芳基-4,5-二氢-1H-吡唑并[3,4-d]嘧啶-4-酮抑制剂的合成及生物学评价。

使用高通量筛选策略，已鉴定出一系列抑制细胞周期蛋白依赖性激酶（CDK）4 /的1-芳基-4,5-二氢-1H-吡唑并[3,4-d]嘧啶-4-酮细胞周期蛋白D1复杂介导的蛋白质底物的磷酸化在低微摩尔范围内的IC（50）s。根据初步的结构-活性关系（SAR），提出了一种模型，其中这些抑制剂占据了酶的ATP结合位点，并与与ATP中的氨基相同的残基（Val96）形成了关键的氢键。假定绑定。对与CDK2结合的新衍生物的X射线衍射研究支持这种结合模式。合成和筛选的反复循环产生了一系列新的有效的CDK2选择性6-（芳基甲基）吡唑并嘧啶酮。将氢键供体放置在6-芳基甲基的间位上会导致CDK4亲和力增加约100倍，从而使配体成为CDK4和CDK2的等价抑制剂。这些化合物在NCI HCT116和其他细胞系中表现出抗增殖作用。这些抗增殖作用的效力在苯胺衍生物中得到增强，并在小鼠异种移植模型中转化为肿瘤生长抑制作用。